1. Field of the Invention
The field of the present invention relates generally to trellis systems for growing vine plants. More particularly, the present invention relates to a latch mechanism for selectively opening or closing trellis systems used to grow vine plants. Even more particularly, the present invention relates to such a mechanism used to support the trellis system for growing vine plants, such as grapes and raisins, by the alternate bearing method of raising such plants.
2. Background
Successful farming operations to grow crops on a commercial basis requires the application of modern horticultural practices. These horticultural practices address the specific requirements and peculiarities of each crop based on what is needed to obtain successful commercialization of the crop. For instance, most crops have certain growing characteristics that can be harmed or improved depending upon the horticultural practices applied by the grower. These characteristics determine how varying amounts of water, sunshine, fertilizer or inclement weather will affect the growth and productivity of the crop. Naturally, it is the goal of each grower to improve the productivity of his or her crops and to maximize crop production from year to year.
The successful commercial production of most varieties of grapes, raisins, and the like is highly influenced by the application of horticultural practices that have been developed over many years. One goal of these horticultural practices has been to reduce the random, uncontrolled growth that is natural for vine plants. Controlling the growth of vine plants such that the vines grow in a relatively restrained and uniform matter can vastly improve crop production. In particular, standard horticultural practices for large scale commercial production of vine crops generally requires vine plant growth be controlled such that the plants grow in a manner which facilitates the introduction of sun light, water and fertilizer and which permits harvesting of the crop in a method consistent with large scale farming operations.
Recently, many growers have begun using sophisticated trellis systems to control the growth of grape, raisin and other vine plants to improve crop production and reduce operating costs. Use of a well-designed trellis system for growing vine plants facilitates the application of irrigation water, fertilizers, insecticides and other grower-supplied materials. A properly installed trellis system will also admit more sunlight to the interior of the vines, which improves crop production and fruit coloration, and ease the harvest of the fruit from the vines. While many trellis systems used for growing vine crops have been successful at obtaining some of the benefits described above, most conventional trellis systems do not obtain all the benefits or to not fully obtain those benefits, particularly improved crop production.
A method of growing vine plants that has been found to be very successful at increasing crop yields is the alternate bearing method described in U.S. Pat. No. 5,711,109 by the present inventor. In summary, the alternate bearing method of growing vine crops has a plurality of vine plants placed in substantially parallel rows with a trellis structure to support and control the vine growth. The grower separates each vine plant into opposing pairs of cordons that are trained to grow along courses supported by the trellis system that are substantially aligned with the rows of plants. Canes produced from each of the four cordons are trained to extend laterally in a side-by-side relation from each cordon over the trellis system toward the center of the path between the rows of vine plants toward the canes of vines growing in the adjacent row of vine plants. Generally, the trellis systems are designed to hold the canes above the earth's surface a sufficient distance to allow workers and equipment to work in the path under the vines and fruit. Each year the path between the rows of vine plants, over which the trellis system extends and the canes are grown, are designated as either a bearing row or a renewal row. The bearing row is allowed to produce fruit from the canes while the renewal row is not (i.e, by cutting the canes), thereby having a field where every other row between the rows of plants is producing fruit. For the following year, the canes that produced fruit the previous year are cut to become the renewal row and the previous renewal row becomes the bearing row and produces fruit. Although the alternate bearing method of growing vine plants results in only one-half of each vine plant growing fruit each year, it has been found to substantially increase crop yield (i.e., typically measured in tons/acre).
To support the vine plants for the alternate bearing method of growing vines, growers generally utilize either a gable trellis system or a flat trellis system. Both types of trellis systems have particular benefits of producing and harvesting the vine plants. Whichever trellis system is used, it must be able to support the weight of the fruit and vines that are make up the bearing rows on the trellis system between every other row of vine plants. Without utilizing an overly massive and cost-prohibited trellis system, the trellis members in between the renewal and bearing rows must be interconnected to support the vines and fruit growing on the alternate bearing rows, thereby creating a trellis system that is closed between rows of vine plants.
Although the closure of the rows between the rows of vine plants is necessary to support the trellis system in the alternate bearing method of growing vine plants, it does result in some reduction in the benefits of a trellis system for vine plants. For instance, because the trellis system is closed at the center of the bearing row, it is more difficult to cut open a space between vines to allow more air and sunlight into the vine plants. It is also more difficult to utilize certain types of mechanical treating and harvesting equipment and to protect the fruit on the vines during inclement weather.
3. Related Art
A number of related art devices address trellis systems used for growing vine plants. One such patent is U.S. Pat. No. 5,711,109 (the "'109 patent") by Gary R. Pitts, the present inventor. In addition to describing the alternate bearing method of growing vines discussed above, the patent describes a trellis system that has been found to be useful for growing plants by the alternate bearing method. The trellis system of the '109 patent utilizes a series of overhead trellis wires (36) that interconnect a series of main transverse cables (35) which in turn interconnect pairs of lateral upright supports (32). Although the transverse cables of the '109 patent provide support for the trellis frames (40) for the alternate bearing method, it produces a closed system. Another such patent is U.S. Pat. No. 5,144,768 (the "'768 patent") to Hiyama, et al., which describes a form of an alternate bearing method that is shown in FIG. 2 as being open between the rows of plants. However, as noted at column 6, lines 32 through 44, the support portions (62) of the non crop bearing rows must be interconnected by wires to counterbalance the weight of the crop on the crop bearing rows. Although the crop bearing row is open, the non crop bearing row is not. The wires are presumably removed each year and moved from one row to the adjacent row, which would not be an easy task.
Each of the aforementioned patents presents an apparatus for supporting a vine plant for use with an alternate bearing method of growing such plants. However, these patents disclose and require the use of either a closed trellis system or a trellis system that requires significant amount of labor to create an open trellis for the crop bearing portion. Therefore, nothing in the prior art known to the inventor discloses an apparatus that provides the benefits of an open trellis system while being able to support the trellises for the alternate bearing method of growing crops. Consequently, a need exists for an apparatus to provide the benefits of an open trellis system that is suitable for use to support either a flat or gable trellis system when used with the alternate bearing method of growing vine plants.